JAMES GRIME: One of the reasons we're fascinated by primes is that they are quite weird in the way they behave. On one hand, they kind of feel random. They are turning up all over the place....
BRADY HARAN: We did a video. I'd done it some time ago about Mersenne primes. And offhandedly, just off the cuff, I said that 1 wasn't a prime. Now, if I'm honest, we...